Cover photograph (Copyright © 2007, American Society for Microbiology. All Rights Reserved.): Electron micrograph view “down the barrel” of rod-shaped Bacillus subtilis cells stacked like cord wood. During cell division, the tubulin-like protein FtsZ forms a ring along the inner circumference of the cell. This ring serves as the scaffold for assembly of the division apparatus and constricts at the leading edge of the invaginating septum during cell division. (Micrograph by Michelle Liberton and Howard Berg at the Danforth Plant Science Center’s Integrated Microscopy Facility; design by Dorothy Gregg.) (See related article on page 9001.)